Storage-state-indicating device



United States Patent Oiilice Re. 25,660 Reissued Oct. 13, 1964 25,660STRAGE-STATE-INDICATING DEVICE Witold M. Modlinski, Los Angeles, Calif.,assigner, by

mesne assignments, to Ampex Corporation, Redwood City, Calif., acorporation of California Original No. 3,110,887, dated Nov. 12, 1963,Ser. No. 821,012, June 17, 1959. Application for reissue Mar. 9, 1964,Ser. No. 367,909

6 Claims. (Cl. 340-174) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This invention relates to data-storage devices employing magnetic coresand, more particularly, to improvements therein.

Storage systems of the type which employ toroidalshaped magnetic cores,each of which has two stable states of magnetic remanence for thepurpose of storing a binary bit of information, have an establishedposition in the information-handling field. Three diiferent types ofmagnetic-core storage apparatus may be employed in anyinformation-handling system` The first type is a randomaccess storagearrangement, which usually is fairly large. The second type is a bufferstorage system, which usually is not random access, nor is it as largeas a random-access system. The smallest form of a memory employing coresis usually called a shift register.

The present invention concerns itself with the form of memory usuallycalled a buffer storage memory, which is not random access but which isloaded with data in a desired loading sequence and is unloaded in thesame sequence as it is loaded. Such a storage system usually lindsapplication where it is desired to transfer data which is received atone rate from apparatus to apparatus which can receive that data atanother rate, which can be higher or lower than the apparatus providingthe data. For eX- ample, if it is desired to transfer data from amagnetic drum to magnetic tape, usually the data is read from the druminto a buifer storage system, and then from the butter storage system tothe magnetic tape.

It is extremely useful to know the state of the storage in a bufferstoragesystem. By that is meant when, for example, in the process ofloading, the buffer storage system has received certain amounts of data,or when in the process of unloading the buffer storage system hasunloaded certain predetermined amounts of data. These signals can beused for initiating the operation of other equipment or terminating theoperation of other equipment which co-operate with the buffer store.

An object of the present invention is to provide a novel arrangement forindicating the state of storage in the magnetic-core memory.

Another object of the present invention is the provision of a uniquearrangement for providing signals each time a magnetic-core storagearrangement attains a predetermined storage state.

Yet another object of the present invention is the provision of a noveland useful system for operating in conjunction with a buffer storagesystem for providing output signals which show the amount of data in thestorage system.

These and other objects of the invention are achieved in an arrangementcomprising the combination with z type of magnetic-core storage system,wherein data i: entered successively in a sequence and is read outsuccessively in the same sequence, of a ring counter. The counterincludes a magnetic core which is associated witl each storage state ofthe magnetic-core memory for whicl an output signal indicative of thatstate is desired. The magnetic cores are arranged in a sequencecorresponding to that of the desired signal sequence. The counter i:initially cleared by driving all but the rst of the core: in thesequence to their clear condition. The rst core i: driven to its setcondition. When the magnetic-cor: memory achieves the state of storagefor which a signa indicative thereof is desired, means are provided fo:driving a magnetic core associated with that state to it: clearcondition and the succeeding magnetic core in th sequence to its setcondition. A reading coil is couplet to all the cores in the counter ina manner whereby ar output is obtained from both the cores which aredriven The novel features that are considered characteristi( of thisinvention are set forth with particularity in th( appended claims. Theinvention itself, both as to it: organization and method of operation,as Well as additional objects and advantages thereof, will best be understood from the following description when read in connection with theaccompanying single figure drawing. which shows in schematic form anembodiment of the invention.

Referring now to the drawing, there may be seen a schematic drawing ofthe embodiment of the invention This shows the invention being employedwith a memory arrangement of the type considered as a buifer storagesystem. Those skilled in the art will appreciate, however, that theconcept of this invention is applicable to different sizes of storagesystems which indeed may be large enough to be full-size memories.Further, the buifer storage system about to be described is not the onlytype with which the embodiment of the invention may be employed. Thusthe description herein is not to be construed as a limitation upon theinvention, but merely exemplary of its applicability.

As is well-known, one preferred arrangement of a magnetic-core storagesystem is the type which utilizes a plurality of magnetic-core planearrays 10, 12, 14, 16. Each one of these will include a plurality ofmagnetic cores, here exemplied by 10A, 12A, 14A, and 16A. These magneticcores are preferably toroidal in shape and have what are commonly calledsubstantially rectangular hysteresis characteristics. Thus, they willhave two stable states of magnetic remanence and are drivable from oneto the other state by the application thereto ol a coercive force whichexceeds a critical value. In each core plane, the cores are arranged incolumns and rows. A row coil, here designated by reference numerals 18,19, 20, 21, and 22, will be inductively coupled to a core in a row whichis correspondingly positioned in every one of the core planes. A columncoil, here identified by reference numerals 23, 24, 25, 26, 27, isinductively coupled to all the cores in a column which is identicallylocated in each one of the core planes. Thus, when current is applied tothe row coil 18, a coercive force is applied to the core 10A, 12A, 14A,16A in each one o the core planes to which the row coil 18 is coupled.Simisasso QJ `.y, should current be applied to the column coil [22] acoercive force is applied to all the correspondingly lated columns ofcores in each one of the core planes the memory. t will be appreciatedthat the representation of the e memory, both with respect to the numberof cores a. core plane, as well as the number of column coils, l thenumber of row coils, is substantially vestigial. s is done in order toavoid complexity in the drawing. :se arrangements are well known.Illustrative thereof basic arrangement shown in an article by J. W. For-:er, entitled Digital Information Storage in Three nensions UsingMagnetic Cores, which is in the rnal of Applied Physics, volume 22, page44, Iany 1951. ior the purpose of storing data, there is first assumedonvention wherein a magnetic core in one state of gnetic remanencerepresents a one and when in the er state of magnetic remanencerepresents a zero. The lmn address source 32 will provide, to a singlecolumn at a time, one-half of the excitation required for ring a corefrom one state of remanence to the other. a row-address source 34 alsoapplies to one row coil a time one-half the current required for drivinga e from one state of remanence to the other. Thus, en the column coil23 and the row coil 1S are excited ultaneously, then only the coreswhich receive a icidence of excitation from the row and column coils lbe driven. These cores are the ones designated by :rence numerals A,12A, 14A, and 16A. The varirow and column coils are excited by theirrespective lress sources in a manner to enter data sequentially i thememory. Thus, successively applying an ex- .tion to row coils 18, 19,20, 21, 22, which are respec- :ly coupled to core groups 10A-16A,10B-16B, -16C, 10D-16D, 10E-16E, and simultaneously and cessively tocolumn coils 23, 24, 25, 26, and 27, can Jlt in successively driving allthe cores 10A through X, all the cores 10B through 16B all the coresthrough 16E. K core in each one of the core planes 10 through 16 l beprevented from being driven by the application of inhibit current fromthe respective inhibit current rces 4t), 42, 44, 46. These inhibitcurrent sources ly a current to an inhibit coil 50, 52, 54, 56 which inh instance is represented vestigially. The inhibit coil :ads every oneof the cores in the plane with which i associated. The current appliedto an inhibit coil by inhibit-current source is usually on the order ofhalt :he value required to drive a core, whereby it can pre- .t the corereceiving both the column and row coil drive rn being driven, and it hassubstantially little or no :ct on the remaining cores in a core plane.nother winding which is provided in each core plane nprises the readingwinding 68, 62, 64, 66, which is i shown vestigially. The function ofthe reading windas is well known, is to have induced therein a voltage acore which is being driven from one to the other :e of magneticremanence. Each one of the reading idings drives a readout amplifier 70,'72, 74, 76. Fhus, for the purpose of entering data in a desired uence,a different row and column coil are excited drive all the cores whichare coupled thereto to repent a binary one. Where it is desired that acore in a e plane represent a binary zero, an inhibit current .rceexcited the inhibit coil simultaneously with excita- 1 of the column androw coil. When it is desired to d out the data which has been enteredinto the memory, column and row address sources are employed to enizethe respective row and column coils in the same uence as the one usedfor entering data. The cores driven toward their one state. Only thosecores which in the zero state will therefore be driven, the others :adybeing in the one state. Thereby, the reading coils i detect where binaryzeros have been stored, and the other coils which will providesubstantially no output indicate that a binary one has been stored inthe particular associated core plane. From the foregoing briefdescription, it will be seen that data is stored successively in groupsof cores, a group comprising, for example, the cores 10A, 12A, 14A, 16A.Each group comprises an identically located core in each one of the coreplanes.

Thus far, there has only been described a known type of buffer-storagearrangement. In accordance with this invention, when it is desired toprovide an indication of the storage state of the buffer-storage systemat various stages of storage, a core, which may be of the same type asthose employed in the memory, is utilized. (These cores are herewithdesignated as marker cores 80, 82, 84, 85, 88. A clear coil isinductively coupled to all the marker cores. This clear coil is drivenfrom a cleara current source 92. The manner of coupling the clear coil90 to all the marker cores is such that the excitation of this coil willdrive the marker core 80 to its one state of remanence, and theremaining marker cores 82, 84, 86, 88 to their Zero states of remanence.Thus, the coil 90 coupled to t-he marker core 80 in one sense and to theremaining marker cores in the opposite sense. A reading coil 94 isinductively coupled to all the marker cores with a diering sense on eachsuccessive core. That is, it is coupled to the marker core 80 with onesense, to the marker core 82 with an opposite sense, to the marker' core84 again in the one sense, to the marker core 86 in an opposite sense,and to the marker core 88 in said one sense. The reading coil appliesany output to aread amplifier 96. The output of the read amplifier 96 isap-4 plied to subsequent utilization apparatus, not shown` The markercores are driven by the same coils which drive a core group with whichthe marker core is to be associated. In other words, if, for example, itis desired to obtain an indication when the th core group is driven(here represented by cores [1013, 12E, 14E, 16E] 10A, 12A, 14A, 16A),then marker core 80, as well as marker core 82, which is a coreassociated with a succeeding core group, are driven by the same columnand row coils which drive the 120th core group. This is achieved bycoupling the column and row coils driving the 120th group (here coils 23and 18) to marker core 80, as Well as marker core 82, which is to beassociated with a succeeding core groupI (which may be, for example, the240th). The sense of the coupling to the marker core 80 is such as todrive it to its zero state of remanence when the row and column coils18, 23 are excited, and to drive the marker core 82 to its one state ofmagnetic remanence.

When the marker cores in the counter are cleared, the marker core 80 isdriven to its one state of remanence; therefore, upon receiving thedrive of the excited row and column coils, it will be driven to its zerostate of magnetic remanence. Marker core 82, however, will be driven toits one state of magnetic remanence. The output which is induced in the`reading coil will therefore be that of both of the cores in View of theopposite coupling sense of the reading winding.

When the row and column coils are excited for driving the succeedinggroup of cores with which the marker core 82 is associated, then themarker core 82 is also driven to its zero-representative state ofremanence, and the marker core S4 simultaneously is driven to its onestate of remanence. The next group of cores, which is here exemplifiedby cores [10D, 12D, 14D, 16D] 10B, 12B, 14B, 16B, are driven when rowcoil 19 and column coil 24 are excited. These coils are coupled to therespective marker cores 82, 84 to respectively be able to drive markercore 82 to its zero state and marker core 84 to its one state. From theabove description, it should become apparent that when it is desired toprovide a signal representative of a state of storage of themagnetic-core memory, the coil or coils which excite the group of coresat the location for which a signal is desired are extended to drive twoadditional marker cores. One of these marker cores, which is the oneassociated with the particular core group, is driven to its zero, orclear, condition, and the marker core associated with the succeedingcore group is driven to its one condition. Thus, row coil and columncoil 25 drive marker cores 84 and 86. Row coil 21 and column coil 26drive marker cores 86 and 88. Row core 22 and column coil 27 drivemarker cores 88 and 80. When the last of the marker cores S8 is drivento its zero state of magnetic remanence, the row and column coils 22,27, which perform this operation, are also coupled to the rst markercore 80 in the sequence to drive it to its one state.

The arrangement of making the marker cores in the form of a ring counteris provided so that when the buffer `storage system is fully loaded withdata, upon subsequent readout of this data, no clearing cycle for themarker cores is necessary. As previously pointed out, the readout ofdata occurs in the same sequence as the data was read into the bufferstorage system. Thus, the use of a ring counter type of operation andalternation of the sense of the read winding allows the marker system tooperate without clearing as the mode of operation of the memory ischanged from loading to unloading. However, should the bulfer storagesystem be only partially loaded before unloading is commenced, then aclearing cycle of operation is necessary. It will be appreciated that asmany of the marker cores as are required may be added, the number shownbeing merely by way of example and not by way of limitation.

There has accordingly been shown and described herein a novel and usefularrangement for providing an output signal for indicating the state ofstorage of a magneticcore storage system. The signals obtained areextremely useful when the storage system is used in conjunction withlarge-scale data-handling systems.

I claim:

1. Apparatus for providing signals indicative of the state of storage ofa magnetic-core memory of the type having a plurality of magnetic coreseach having two states of stable remanence whereby it may represent abit of binary data, said plurality of cores being arranged in aplurality of groups with coil means being coupled to said core groupsfor entering data and for reading out data, said magnetic-core memoryincluding means for energizing said coil means for entering data intosaid core groups in a predetermined sequence and for reading out data inthe same sequence, said apparatus for providing signals including amagnetic marker core associated with each group of cores in said memoryat which it is desired to provide an indicating signal, each marker corehaving two stable states of remanence respectively representing one andzero and being drivable from one to the other of said states, means fordriving to its one state the marker core associated wi-th the earliestcore group in the dataentering sequence and for driving all said othermarker cores to their zero states, means for driving each marker core toits zero state when the coil means of the associated core group isenergized by said means for energizing and for driving the succeedingmarker core to its one sta-te, and means for deriving an output signalfrom the two driven marker cores.

2. Apparatus for providing signals indicative of the state of storage ofa magnetic-core memory of the type having a plurality of magnetic coreseach having two states of stable remanence whereby it may represent abit of binary data, said plurality of cores being arranged in groups andhaving a plurality of separate coils coupled thereto for successivelyentering data into the core groups and for successively reading out datafrom said core groups, said magnetic-core memory including means forenergizing said coils for entering data into a group of cores in apredetermined sequence and for reading out data in the same sequence,said apparatus for providing signals including a ring counter having amagnetic-marker core associated with each group of cores in said memoryat which it is desired to provide an indicating signal, each marker corehaving two stable states of remanence respectively representing one andzero and being drivable from one to the other of said states, means fordriving to its one state the marker c`ore associated with the earliestof the groups of cores in the data-entering sequence and for driving allsaid other marker cores to their zero states, means for coupling thecoils which enter data into a group of cores to an associated markercore in one sense and to the succeeding marker core with a senseopposite to said one sense for driving said associated marker core toits zero state and said succeeding marker core to its one state whensaid coils are energized by said means for energizing said coils, andmeans for deriving an output signal from the two driven marker cores.

3. Apparatus as recited in claim 2 wherein said means for deriving anoutput signal from .the two driven marker cores comprise a reading coilinductively coupled to all said marker cores, the sense of said couplingon a core being reversed from the sense of said coupling on adjacentcores.

4. The combination with a magnetic-core memory of apparatus forsignaling the storage state of said memory, said magnetic-core memorybeing of the type having a plurali-ty of matrices, each matrix having aplurality of magnetic cores, each core having two states of stableremanence whereby it may represent a bit of binary data, said pluralityof cores in each matrix being arranged in columns and rows, a group ofcores for data storage being comprised of a similarly located core ineach of the matrices, data entry into the groups of cores of said Inemory and data readout occurring in the same predetermined sequence, saidapparatus comprising a magnetic-marker core associated with each groupof cores for which a signal is desired, each marker core having twostable states of remanence respectively representing one and zero andbeing drivable from one to the other of said states, coil means coupledto all said marker cores for driving to its one state the marker coreassociated with the earliest of the groups of cores in the data-enteringsequence and for driving all said other marker cores to their zerostates, a separate coil means coupled to each group of cores for drivingsaid cores for data entry and data readout, those of said coil meanswhich are coupled to a group of cores with which a marker is associatedbeing alsol coupled to the associated marker core with one sense and tothe succeeding core with a sense opposite to said one sense, the coilmeans which is coupled to the last marker core with one sense beingcoupled to the iirst marker core with a sense opposite to said onesense, and a readout coil coupled to all said marker cores the sense ofthe coupling on a marker core being opposite to :the sense of thecoupling on adjacent marker cores.

5. The combination recited in claim 4 wherein said separate coil meanscoupled to each group of cores for driving said cores for data entry anddata readout includes for each group of cores a row coil which iscoupled to all the cores in similarly located rows in said plurality ofmatrices, and a column coil which is coupled to all the cores insimilarly located columns in said plurality of matrices.

6. The combination with a magnetic-core memory of apparatus forsignaling when several stages of storage capacity of said memory havebeen attained comprising a ring counter including a magnetic core foreach stage of storage capacity for which an indication is desired, eachof said cores having two stable states of remanence respectivelyrepresenting one and zero and being drivable from one tothe other, eachof said cores being assigned for signaling a diiferent Stage of storagecapacity, means for clearing said ring counter including a coil coupledto the rst of said cores in one sense and to the others of said cores ina sense opposite to said one sense, means for storing data in saidmagnetic-core memory in a desired sequence and for reading out storeddata in the same sequence, said last-named means including means fordriving a core to its zero state of remanence when said memory reachesthe stage of storage capacity to which said core has been assigned andfor driving the succeeding core in said counter to its one state, andmeans for deriving an output from the driven corres including a coilcoupled to each succeeding driven core with a sense opposite 10 to thesense of coupling tov a preceding core.

I g ,t

References Cited by the Examiner The following references, cited by theexaminer, are of record in the patented file or the original of thispatent UNITED STATES PATENTS 2,691,156 10/54 Saltz.

2,709,248 5/55 Rosenberg. 2,768,367 10/56 Rajchman. 2,778,006 1/57Guterman.

IRVlNG L. SRAGOW, Primary Examiner.

